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1.
Environ Pollut ; 346: 123688, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38431247

RESUMO

One challenge of the citrus industry is the treatment and disposal of its effluents due to their high toxicity, substantial organic load, and consequent resistance to conventional biotechnological processes. This study introduces a novel approach, using electrochemical oxidation with a boron-doped diamond anode to efficiently remove organic compounds from biodegraded pulp wash (treated using the fungus Pleurotus sajor-caju.) The findings reveal that employing a current density of 20 mA cm-2 achieves notable results, including a 44.1% reduction in color, a 70.0% decrease in chemical oxygen demand, an 88.0% reduction in turbidity, and an impressive 99.7% removal of total organic carbon (TOC) after 6 h of electrolysis. The energy consumption was estimated at 2.93 kWh g-1 of removed TOC. This sequential biological-electrochemical procedure not only significantly reduced the mortality rate (85%) of Danio rerio embryos but also reduced the incidence of morphologically altered parameters. Regarding acute toxicity (LC50) of the residue, the process demonstrated a mortality reduction of 6.97% for D. rerio and a 40.88% lethality decrease for Lactuca sativa seeds. The substantial reduction in toxicity and organic load observed in this study highlights the potential applicability of combined biological and electrochemical treatments for real agroindustrial residues or their effluents.


Assuntos
Diamante , Poluentes Químicos da Água , Diamante/química , Poluentes Químicos da Água/análise , Eletrólise/métodos , Compostos Orgânicos , Eletrodos , Oxirredução
2.
Environ Sci Pollut Res Int ; 31(18): 27388-27402, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38512573

RESUMO

In aluminum electrolysis, the iron-rich cover material is formed on the cover material and the steel rod connecting the carbon anode. Due to the high iron content in the iron-rich cover material, it differs from traditional cover material and thus requires harmless recycling and treatment. A process was proposed and used in this study to recovery F, Al, and Fe elements from the iron-rich cover material. This process involved aluminum sulfate solution leaching for fluorine recovery and alkali-acid synergistic leaching for α-Al2O3 and Fe2O3 recovery were obtained. The optimal leaching rates for F, Na, Ca, Fe, and Si were 93.92, 96.25, 94.53, 4.48, and 28.87%, respectively. The leaching solution and leaching residue were obtained. The leaching solution was neutralized to obtain the aluminum hydroxide fluoride hydrate (AHFH, AlF1.5(OH)1.5·(H2O)0.375). AHFH was calcined to form a mixture of AlF3 and Al2O3 with a purity of 96.14%. The overall recovery rate of F in the entire process was 92.36%. Additionally, the leaching residue was sequentially leached with alkali and acid to obtain the acid leach residue α-Al2O3. The pH of the acid-leached solution was adjusted to produce a black-brown precipitate, which was converted to Fe2O3 under a high-temperature calcination, and the recovery rate of Fe in the whole process was 94.54%. Therefore, this study provides a new method for recovering F, Al, and Fe in iron-rich cover material, enabling the utilization of aluminum hazardous waste sources.


Assuntos
Óxido de Alumínio , Alumínio , Eletrólise , Compostos Férricos , Fluoretos , Compostos Férricos/química , Alumínio/química , Fluoretos/química , Óxido de Alumínio/química , Ferro/química , Compostos de Alumínio/química , Reciclagem
3.
Water Res ; 253: 121312, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38367383

RESUMO

Two iron-electrolysis assisted anammox/denitrification (EAD) systems, including the suspended sludge reactor (ESR) and biofilm reactor (EMR) were constructed for mainstream wastewater treatment, achieving 84.51±4.38 % and 87.23±3.31 % of TN removal efficiencies, respectively. Sludge extracellular polymeric substances (EPS) analysis, cell apoptosis detection and microbial analysis demonstrated that the strengthened cell lysate/apoptosis and EPS production acted as supplemental carbon sources to provide new ecological niches for heterotrophic bacteria. Therefore, NO3--N accumulated intrinsically during anammox reaction was reduced. The rising cell lysis and apoptosis in the ESR induced the decline of anammox and enzyme activities. In contrast, this inhibition was scavenged in EMR because of the more favorable environment and the significant increase in EPS. Moreover, ESR and EMR achieved efficient phosphorus removal (96.98±5.24 % and 96.98±4.35 %) due to the continued release of Fe2+ by the in-situ corrosion of iron anodes. The X-ray diffraction (XRD) indicated that vivianite was the dominant P recovery product in EAD systems. The anaerobic microenvironment and the abundant EPS in the biofilm system showed essential benefits in the mineralization of vivianite.


Assuntos
Compostos Ferrosos , Nitratos , Fosfatos , Esgotos , Águas Residuárias , Desnitrificação , Fósforo , Ferro , Oxidação Anaeróbia da Amônia , Eletrólise , Reatores Biológicos/microbiologia , Nitrogênio , Oxirredução
5.
J Environ Manage ; 351: 119848, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38113787

RESUMO

To efficiently remove nutrients from low C/N sanitary sewage by conventional biological process is challenging due to the lack of sufficient electron donors. A novel electrolysis-integrated sequencing batch biofilm reactor (E-SBBR) was established to promote nitrogen and phosphorus removal for sanitary sewage with low C/N ratios (3.5-1.5). Highly efficient removal of nitrogen (>79%) and phosphorus (>97%) was achieved in the E-SBBR operating under alternating anoxic/electrolysis-anoxic/aerobic conditions. The coexistence of autotrophic nitrifiers, electron transfer-related bacteria, and heterotrophic and autohydrogenotrophic denitrifiers indicated synergistic nitrogen removal via multiple nitrogen-removing pathways. Electrolysis application induced microbial anoxic ammonia oxidation, autohydrogenotrophic denitrification and electrocoagulation processes. Deinococcus enriched on the electrodes were likely to mediate the electricity-driven ammonia oxidation which promoted ammonia removal. PICRUSt2 indicated that the relative abundances of key genes (hyaA and hyaB) associated with hydrogen oxidation significantly increased with the decreasing C/N ratios. The high autohydrogenotrophic denitrification rates during the electrolysis-anoxic period could compensate for the decreased heterotrophic rates resulting from insufficient carbon sources and nitrate removal was dramatically enhanced. Electrocoagulation with iron anode was responsible for phosphorus removal. This study provides insights into mechanisms by which electrochemically assisted biological systems enhance nutrient removal for low C/N sanitary sewage.


Assuntos
Desnitrificação , Esgotos , Nitrificação , Amônia , Reatores Biológicos/microbiologia , Nitrogênio/metabolismo , Eletrólise , Biofilmes , Nutrientes , Fósforo
6.
Water Res ; 247: 120789, 2023 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-37922639

RESUMO

A wastewater treatment plant with a large inflow of phosphorus (P) is a potential P source that can act as an alternative to phosphate rocks and a renewable source of P. During electrolysis with inert electrodes, hydroxide ions generated from the cathode cause calcium phosphate (CaP) precipitation, and oxygen and hydrogen generated from the electrodes cause thickening of the sludge by electroflotation in sludge treatment streams. However, these two effects have not been achieved simultaneously because the precipitation of CaP requires much more time than that required for thickening by electroflotation. In this study, an electrolysis system that used an anode covered with bivalve shells was used. Batch experiments were conducted and the results demonstrated that covering the anode with shells resulted in their dissolution and that the calcium ions provided by this process considerably enhanced P removal in the form of CaP, thereby shortening the time required for CaP precipitation. In continuous experiments with excess sludge, electrolysis with shells accomplished sludge thickening by electroflotation (the thickened sludge had 5.5 times the total solids in the original excess sludge) and low relative phosphate-P concentrations (0.0545-0.0812) in the effluent compared to the influent. This effect is attributed to CaP precipitation. Additional mixing of the CaP precipitates in the effluent enhanced their settleability. The results demonstrate that electrolysis using an anode covered with bivalve shells simultaneously achieved CaP precipitation and sludge thickening.


Assuntos
Fósforo , Esgotos , Eletrólise , Fosfatos , Íons , Eletrodos
7.
J Back Musculoskelet Rehabil ; 36(5): 1033-1046, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37458028

RESUMO

BACKGROUND: Physical therapists use dry needling (DN) and percutaneous needle electrolysis (PNE) to treat musculoskeletal pain. OBJECTIVE: To investigate the efficacy of PNE vs. DN in the treatment of musculoskeletal pain. METHODS: This systematic review and meta-analysis was based on the PICOS and PRISMA protocols. The PubMed, PEDro, Cochrane Library, SCOPUS, and Google Scholar databases were searched for randomized clinical trials measuring pain intensity in various musculoskeletal syndromes using PNE and DN. Pain outcome measures were the visual analog scale or the numerical pain rating scale. Risk of bias was assessed according to Cochrane guidelines and quality of evidence was reported using the Grading of Recommendations Assessment, Development, and Evaluation approach (GRADE). Standardized mean differences were calculated using random effects models. RESULTS: The meta-analysis of the six included studies showed that the overall effect of PNE vs. DN for pain reduction was statistically significant at -0.74 (95% confidence interval [CI], -1.34 to -0.14) with a large effect size (SMD =-0.41; 95% CI, -0.75 to -0.08), albeit clinically insignificant in the short, medium, and long term. Risk of bias was generally low with moderate-level evidence due to the overall effect heterogeneity and the small sample. CONCLUSIONS: Moderate-quality evidence showed that PNE is slightly more effective than DN in reducing pain. However, because the results were not clinically significant, we cannot recommend the application of PNE over DN. More high-quality studies comparing the two interventions are needed to draw firm conclusions.


Assuntos
Agulhamento Seco , Dor Musculoesquelética , Humanos , Dor Musculoesquelética/terapia , Avaliação de Resultados em Cuidados de Saúde , Manejo da Dor/métodos , Eletrólise
8.
Chemosphere ; 319: 138013, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36731662

RESUMO

Removing petroleum hydrocarbons (PHCs) from polluted soil is challenging due to their low bioavailability and degradability. In this study, an experiment was carried out to treat soil polluted with petroleum hydrocarbon using a hybrid electro-Fenton (with BDD anode electrode) and biological processes stimulated with long-chain rhamnolipids (biosurfactants). Electro-Fenton treatment was applied as a pretreatment before the biological process to enhance PHC biodegradability, which would benefit the subsequent biological process. The effects of initial pH, hydroxide concentration, soil organic matter composition, PHCs intermediates during the electro-Fenton process, and total numbers of bacteria in the biological process were analyzed to determine the optimum conditions. The results showed that the optimized electrolysis time for the electro-Fenton was 12 h. The change induced during pretreatment at a specified time was found suitable for the biological process stage and led to 93.6% PHC degradation in combination with the electro-Fenton-and-biological process after 72 h. The combined system's performance was almost 40% higher than individual electro-Fenton and biological treatments. GC-MS analysis confirms the formation of 9-octadecen-1-ol (Z), 2-heptadecene, 1-nonadecene, 1-heneicosene, and pentacosane as fragmentation during the PHCs degradation process. Thus, the electro-Fenton process as pretreatment combined with a biological process stimulated with rhamnolipids (biosurfactants) could be effectively applied to remediate soil polluted with PHCs. However, the system needs further research and investigation to optimize electrolysis time and biosurfactant dose to advance this approach in the soil remediation process.


Assuntos
Petróleo , Poluentes do Solo , Solo/química , Hidrocarbonetos , Eletrólise , Cromatografia Gasosa-Espectrometria de Massas , Poluentes do Solo/química , Peróxido de Hidrogênio/química
9.
J Colloid Interface Sci ; 630(Pt B): 844-854, 2023 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-36356450

RESUMO

Seawater electrolysis is considered to be very challenging owing to competitive reaction kinetics in between oxygen evolution reaction and corrosive chlorine evolution reaction mechanism at anode, especially towards higher current density. The present work, proposes a promising and energy efficient strategy by coupling seawater splitting with urea decomposition lowering oxidation potential and thereby avoiding hypochlorite formation even at high current density. The rational design of Mott-Schottky heterojunction of Se/NiSe2 as electrocatalyst is considered to be highly effective in this regard. The developed Se/NiSe2 exhibits extraordinary energy saving for alkaline seawater splitting in presence of urea. The Se/NiSe2/NF || Se/NiSe2/NF electrolyser configuration achieved 10 and 50 mAcm-2 current densities with cell voltage of 1.59 and 1.70 V along with outstanding operational durability over 50 h. The large number of carrier density generates by synergistic self-driven electron transfer from Se to NiSe2 at the heterojunction, unique metallic properties of selenium (Se), and also abundance accessible reactive edges on the porous channel of Ni foam are believed to be the reason behind such enhanced electrocatalytic activities towards urea oxidation reaction and hydrogen evolution reaction offering unique and much energy saving approach for alkaline-urea-seawater electrolysis avoiding hypochlorite formation.


Assuntos
Selênio , Ureia , Ácido Hipocloroso , Conservação de Recursos Energéticos , Eletrólise , Água do Mar , Hidrogênio
10.
Chemosphere ; 313: 137415, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36464016

RESUMO

Improving the sustainability of the hydraulic fracturing water cycle of unconventional oil and gas development needs an advanced water treatment that can efferently treat flowback and produced water (FPW). In this study, we developed a robust two-stage process that combines flocculation, and iron-carbon micro-electrolysis plus sodium persulfate (ICEPS) advanced oxidation to treat field-based FPW from the Sulige tight gas field, China. Influencing factors and optimal conditions of the flocculation-ICEPS process were investigated. The flocculation-ICEPS system at optimal conditions sufficiently removed the total organic contents (95.71%), suspended solids (92.4%), and chroma (97.5%), but the reaction stoichiometric efficiency (RSE) value was generally less than 5%. The particles and chroma were effectively removed by flocculation, and the organic contents was mainly removed by the ICEPS system. Fourier-transform infrared spectroscopy (FTIR) analysis was performed to track the changes in FPW chemical compositions through the oxidation of the ICEPS process. Multiple analyses demonstrated that PS was involved in the activation of Fe oxides and hydroxides accreted on the surface of the ICE system for FPW treatment, which led to increasing organics removal rate of the ICEPS system compared to the conventional ICE system. Our study suggests that the flocculation-ICEPS system is a promising FPW treatment process, which provides technical and mechanistic foundations for further field application.


Assuntos
Fraturamento Hidráulico , Poluentes Químicos da Água , Águas Residuárias , Carbono/análise , Ferro/análise , Poluentes Químicos da Água/análise , Eletrólise
11.
Environ Sci Pollut Res Int ; 30(5): 13372-13392, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36131176

RESUMO

Iron-carbon micro-electrolysis is effective for the removal of phosphorus in wastewater; however, meeting the stringent emission standards required for treatment is difficult. To meet these treatment standards, modified micro-electrolytic fillers were prepared from iron dust, powdered activated carbon, clay, and additives using an elevated temperature roasting process under an inert atmosphere. The results show that among several additives, the modified micro-electrolytic (Fe/C-MgCO3) fillers using MgCO3 were the most effective at phosphorus removal. The preparation conditions for the Fe/C-MgCO3 fillers and their effects on phosphorus removal performance were investigated. Under the optimal preparation conditions (calcination temperature: 800 °C, Fe/C = 4:1, clay content 20%, and 5% MgCO3), the filler yielded a high compressive strength of 3.5 MPa, 1 h water absorption rate of 25.7%, and specific surface area and apparent density of 154.2 m2/g and 2689.2 kg/m3, respectively. The iron-carbon micro-electrolysis process removed 97% of phosphorus in the wastewater by using the Fe/C-MgCO3 fillers, which was 14% more than the Fe/C filler. Electrostatic adsorption and surface precipitation were identified as the main phosphorus removal mechanisms, and the surface of the Fe/C-MgCO3 filler was continuously updated. These results demonstrated that Fe/C-MgCO3 is a promising filler for phosphorus removal in water treatment.


Assuntos
Fósforo , Águas Residuárias , Argila , Eletrólise/métodos , Ferro , Eliminação de Resíduos Líquidos/métodos
12.
Water Sci Technol ; 86(10): 2581-2592, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36450674

RESUMO

In this study, the iron-carbon-aluminum (Fe-C-Al) composite filler was prepared by aluminum modification of conventional iron-carbon (Fe-C) micro-electrolysis with a no-burn method. The optimal process conditions for Fe-C-Al three-phase micro-electrolysis treatment of low concentration phosphorus wastewater were determined to be the aluminum metal ratio of 14 wt% and solids dosing of 30 g/L. Under the optimal process conditions, Fe-C-Al three-phase micro-electrolysis was performed for the treatment of low concentration phosphorus wastewater (LCPW) with continuous experiment, while iron-carbon fillers before and after treatment were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that the amount of Fe2+ dissolved in the micro-electrolysis determined the micro-electrolysis phosphorus removal effect, Al promoted the dissolution of Fe2+, and the Fe-C-Al filler had a stable phosphorus removal effect, and the average removal efficiency of phosphorus was 67.40%, which is an average improvement of 29.25% compared with the conventional Fe-C filler. The treatment of LCPW by Fe-C-Al three-phase micro-electrolysis is consistent with a first-order kinetic reaction with apparent activation energy of 38.70 kJ·mol-1, which is controlled by the chemical reaction.


Assuntos
Alumínio , Águas Residuárias , Eletrólise , Fósforo , Carbono , Ferro
13.
Water Res ; 226: 119277, 2022 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-36283230

RESUMO

Microplastics have been identified as a kind of emerging pollutant with potential ecological risks, and it is an urgent endeavor to find proper technologies for their remediation. Electrochemical advanced oxidation process (EAOP) technology has exhibited robust performance in the removal of various refractory organic pollutants. In this study, we explored a new remediation strategy for polystyrene microplastics (PS MPs), introducing sodium dodecyl sulfate (SDS) to enhance its degradation performance in boron-doped diamond (BDD) anode adopted EAOP. At first, we investigated the degradation behaviors of SDS in the BDD electrolysis. According to the SDS half-life under various current densities, the SDS addition strategy into EAOP is proposed; that is, supplement SDS to 500 mg/L at every half-life during electrolysis except the last cycle. Results indicated that SDS addition greatly enhanced MPs degradation rate in 72 h of EAOP, about 1.35-2.29 times higher than that in BDD electrolysis alone. The SDS assisted EAOP also led to more obvious changes in the particle size, morphology, and functional groups of the MPs. After treatment, a variety of alkyl-cleavage and oxidation products were identified, which attributed to the strong attack of oxidants (i.e., persulfate) on the MPs. The enhanced persulfate generation and oxidants adsorption on MPs can explain the enhancement effect in the EAOP strategy. Cost analysis results showed the surfactant only accounts for < 0.05% of the total operating costs in the SDS assisted EAOP. In general, the current study provided new insight into the effective way to improve the EAOP efficiency of microplastics.


Assuntos
Microplásticos , Poluentes Químicos da Água , Dodecilsulfato de Sódio , Tensoativos , Poliestirenos , Plásticos , Diamante , Eletrólise/métodos , Boro , Oxirredução , Eletrodos , Oxidantes
14.
Rev. Eugenio Espejo ; 16(3): 119-135, 20220819.
Artigo em Espanhol | LILACS | ID: biblio-1393247

RESUMO

La electrólisis percutánea intratisular es un procedimiento terapéutico tecnológico mínimamente invasivo para el tratamiento de lesiones en el sistema musculoesquelético mediante inflamación controlada y fagocitosis para recuperar el tejido afectado. Acerca de esta, se realizó un análisis de la producción científica publicada de 2014 a 2021. El estudio se realizó por medio de una revi-sión bibliográfica sistémica siguiendo la metodología PRISMA, que incluyó el uso de fuentes de información en las bases científicas: PubMed, SciencieDirect, EuropePMC, ResearchGate, Sage Journal, Thiem Connect y PHysiotherapy evidence database (PEdro). Previamente al procesa-miento de los datos, los documentos encontrados fueron sometidos diversos criterios de selec-ción. Los investigadores concluyeron que la electrólisis percutánea intratisular resulta un trata-miento efectivo para el tratamiento de tendinopatías crónicas, cuando se realiza combinado con un programa de ejercicios enfocado en la progresión de las cargas.


This work presents an analysis of the scientific production developed between 2014 and 2021 on percutaneous intratissue electrolysis. The objective is to analyze the bibliograpHy on the diffe-rent EPI interventions. The study was carried out through a systemic review following a methodological process according to PRISMA using various sources for the collection of information, such as: Pubmed, Scienciedirect, Europe PMC, Hindawi, Cochrane, Sage Journal, Thiem Connect, Pedro, Puerta Of the investigation. Selection and quality criteria were applied to these documents, with a subsequent analysis using qualitative techniques. In conclusion, intratissue percutaneous electrolysis turns out to be a favorable tool in the treatment of chronic tendinopathies as long as it is combined with an exercise program focused on load progression.


Assuntos
Humanos , Masculino , Feminino , Administração Cutânea , Eletrólise , Sistema Musculoesquelético , Bibliografia , PubMed , Revisão Sistemática
15.
Chemosphere ; 307(Pt 2): 135765, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-35870605

RESUMO

This study investigated the potential of a novel fabricated black phosphorus (BP) nanoparticle electrode as an alternative to noble metal-based catalysts for application in electrolysis. The BP electrode was compared with other conventional catalysts (boron-doped diamond (BDD) and a dimensional stable electrode (DSA)) under different electrolyte conditions for the generation of specific oxidants (e.g., OH•, HOCl, OCl-, SO4• -) in the bulk phase during electrolysis. In the presence of sulfate-based electrolyte, results on the electrochemical oxidation showed that the BP not only resulted in an 8-fold increase in the current efficiency compared to DSA, but also reduced energy consumptions by approximately 30-fold. Moreover, electrolysis using certain electrodes (i.e., BDD) under high current densities in the presence of chlorine-based electrolyte has been reported to be hazardous to the water system due to the generation of toxic chlorine oxyanions (i.e., perchlorate), which necessitates the operation of a post-treatment process. Likewise, application of the BDD electrode was confirmed to produce perchlorate under high current densities, while no by-product was generated by electrolysis with the BP electrode. Finally, multiple degradation pathways for selective water treatment was monitored under oxidation with the BP electrode. To the best of our knowledge, this study is the first to apply the novel fabricated BP electrode as the anodic catalyst for the treatment of a water system.


Assuntos
Boro , Poluentes Químicos da Água , Cloro , Diamante , Eletrodos , Eletrólise/métodos , Oxidantes , Oxirredução , Percloratos , Fósforo , Sulfatos
16.
Environ Sci Pollut Res Int ; 29(54): 82574-82583, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-35752668

RESUMO

A novel method for remediating eutrophic lakes through electrolysis was made possible by one titanium (Ti) mesh, which serves as a cathode and two anodes of Ti mesh coated with ruthenium (IV) oxide and iridium (IV) oxide (RuO2-IrO2/Ti). Once the three-electrode components RuO2-IrO2/Ti and Ti are stabilized, they can carry out electrolytic reaction to control cyanobacteria blooms and assist with the remediation of eutrophic water. The order of influence on the theoretical energy consumption involved in removing algae is as follows: The electrode spacing was more effective than electrode voltage, which proved more effective than electrolysis time through the orthogonal test method. Thus, an electrode spacing of 60 mm, an electrode voltage of 30 V, and an electrolysis time of 12 h are the optimal electrolysis methods used to remove cyanobacterial blooms. The strong acidic environment produced by the anode increased the concentration of hydroxyl radical (•OH) and other strong oxidizing substances, which were the main roles that made cyanobacteria bloom inactivation. The electrolysis reaction was conducive to the transformation of organophosphorus in cyanobacterial blooms to dissolved inorganic phosphorus (DIP) in water. Some DIP was most deposited on the cathode after electro-depositing enhanced the removal of P in water with the 12-h prolonged electrolysis time. Meanwhile, it was beneficial to reduce the total nitrogen (TN) and ammonia nitrogen (NH3-N) in the water. Thus, electrolysis proved to be an effective way to the inactivation of cyanobacteria blooms and simultaneously recover P as the concentration became higher.


Assuntos
Cianobactérias , Rutênio , Fósforo , Amônia , Titânio , Irídio , Radical Hidroxila , Eletrólise , Nitrogênio , Eletrodos , Óxidos , Água , Eutrofização
17.
Sci Total Environ ; 843: 156914, 2022 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-35753464

RESUMO

Phosphorus (P) recovery from waste streams is an essential choice due to the coming global P crisis. One promising solution is to recover P by microbial electrolysis cell (MEC). Both the P recovery effectiveness and product quality are of critical importance for application. In this study, a two-chamber MEC was constructed and the effects of applied voltage, NaAc concentration, Mg/P molar ratio, N/P molar ratio, and initial P concentration on P recovery and product purity were explored. The maximum P recovery efficiency of 99.64 % and crystal accumulation rate over 106.49 g/m3-d were achieved. Struvite (MAP) was confirmed as the final recovered product and the purity obtained could reach up to 99.95 %. Besides, higher applied voltage, N/P molar ratio and initial P concentration could promote P recovery efficiency, while the purity of MAP showed correlation with applied voltage, Mg/P molar ratio, N/P molar ratio and initial P concentration. The correlation between NaAc concentration and both of the above was not very significant. A lower energy consumption of 4.1 kWh/kg P was observed at the maximum P recovery efficiency. In addition, the efficiency of P recovery from real wastewater also could reach nearly 88.25 %. These results highlight the promising potential of efficient phosphorus recovery from P-rich wastewater by MEC.


Assuntos
Fósforo , Aço Inoxidável , Eletrodos , Eletrólise , Fosfatos/química , Fósforo/química , Estruvita , Águas Residuárias/química
18.
Bull Environ Contam Toxicol ; 109(1): 101-109, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35552770

RESUMO

The Bayer red mud is the solid waste generated during the production of alumina by the Bayer process. At present, the stock of red mud in China exceeds 1.1 billion tons, covering an area of more than 120,000 mu, and the annual production volume is increasing by 100 million tons. The comprehensive utilization of red mud is still a difficult problem. Therefore, it is of great significance to actively explore new methods for removing sodium from red mud. In this study, the traditional red mud desalination process and the slurry electrolysis process are combined, and the influence of three different leaching agents on the leaching and sodium removal of red mud slurry in the presence of an electric field is explored. In the slurry electrolysis experiment, it was found that the sodium removal rate obtained by different leaching agents was CaO > CaCl2 > HCl. The red mud leached with pure dilute hydrochloric acid has the highest Na removal rate, which is 93.11%. In view of this situation, a pre-slurry-electrolysis cycle process with HCl as leaching agent was proposed. The core of slurry electrolysis is electrolyzing NaCl solution, and HCl only participates in the process as circulating medium. The design of this process reduces cost and increases efficiency.


Assuntos
Óxido de Alumínio , Eletrólise , China , Sódio
19.
Food Chem ; 389: 133129, 2022 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-35526291

RESUMO

Slightly acidic electrolyzed water (SAEW) is often used on eggs to remove microorganisms, but the cuticle will be damaged, causing bacterial invasion and deterioration of egg quality during preservation. Therefore, a combination of SAEW disinfection with chitosan (CS) and pectin (PT) composite coating (CS + PT) was tried in preventing bacterial invasion and prolonging the shelf life of eggs. The results showed the order of decontamination effectiveness on contaminated eggs was SAEW > Electrolyzed reduced water (ERW) + SAEW > ERW > deionized water. The CS + PT coating used on SAEW-disinfected eggs inhibits the S. enteritidis invasion (reduced by 63.3%) and was successfully used to maintain the quality of eggs (Haugh unit 48.63, Weight loss 7.34%, Yolk index 0.29, pH 8.93) after 8 weeks storage at 25 ℃. The results revealed that the combination of SAEW and CS + PT was a very promising method for egg preservation.


Assuntos
Quitosana , Ácidos , Quitosana/farmacologia , Ovos , Eletrólise , Concentração de Íons de Hidrogênio , Pectinas , Salmonella enteritidis , Água/química
20.
Chemosphere ; 301: 134762, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35490751

RESUMO

Aiming at the problems of lack of carbon sources for nitrogen removal and low phosphorus removal efficiency of constructed wetlands (CWs) in treating wastewater treatment plant (WWTP) effluent, an electrolysis assisted constructed wetland (E-CW) with coconut fiber as substrate and solid carbon sources was constructed. The synthetic secondary effluent was used as the influent of the E-CW with a wastewater treatment capacity of 140 L d-1. The total nitrogen (TN) and the total phosphorus (TP) removal efficiency of the E-CW with coconut fiber treating WWTP effluent were 69.4% and 93.3%, respectively, which were 54.3% and 88.2% higher than those of CW with coconut fiber and no electrolysis. The removal efficiency of TN was 39.9% higher than that of E-CW with gravel. The current intensity had significant effect on nitrogen removal efficiency and the release of carbon sources from coconut fiber. When current intensity increased from 0.25 A to 1.00 A, the TN removal efficiency and nitrate removal rate increased by 21.1% and 0.21 mg L-1 h-1, respectively, and the volatile fatty acids (VFAs) released from coconut fiber increased by 57.7 mg L-1. The 16S rRNA high-throughput sequencing results indicated that the main functional nitrogen-removing microbes were Hydrogenophaga, Thauera, Rhodanobacteraceae_norank, Xanthobacteraceae_norank, etc. Multiple paths including autotrophic denitrification with hydrogen and Fe2+ as electron donors and heterotrophic denitrification were achieved in the system. Meanwhile, the main functional lignocellulose degradation microbes were enriched in the system, including Cytophaga_xylanolytica_group, and Caldilineaceae. Because electrolysis created a favorable environment for them to release carbon sources from coconut fiber. This study provided a new perspective for advanced nutrients removal of WWTP effluent in CWs.


Assuntos
Desnitrificação , Áreas Alagadas , Carbono , Cocos , Eletrólise , Nitrogênio , Fósforo , RNA Ribossômico 16S , Eliminação de Resíduos Líquidos/métodos , Águas Residuárias
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